巻号一覧
35 巻, 6 号
選択された号の論文の17件中1～17を表示しています
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黒木 英憲, 中村 真知也, 片島 三朗1988 年 35 巻 6 号 p. 469-472
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーCompacting pressures similar to those for P/M parts were applied to alumina-based ceramic granules, which were produced for IC-substrates, to investigate the spring-back during compacting and the shrinkage during sintering. Cylinders, d10 × h10 mm, were compacted with die-wall lubrication under 50-800 MPa. They were heated in air at the rate of 3.5°C/min, and held at 600°C for 10 min for dewaxing and at 1400°C for 2 hr for sintering.
The axial spring-back was measured with a couple of electric micrometers attached to the punches. The radial spring-back was derived from the diametral difference between the die and the compact.
The spring-back of the granules was larger than those of the iron and copper powders. Increased compacting pressure led to increased green density, accompanied by increased axial spring-back by the unloading and decreased axial spring-back by the ejecting. It also led to decreased shrinkage in both directions during the sintering.抄録全体を表示PDF形式でダウンロード (1541K) -
黒木 英憲, 中村 真知也, 片島 三朗1988 年 35 巻 6 号 p. 473-478
発行日: 1988/09/25
公開日: 2009/12/04
ジャーナル フリーAlumina preforms, d10×h10 mm in size, were made without pressing of a powder having an average particle size of 2.6 μm and containing 0.51-1.5 mass% polyvinyl alcohol. The preforms were pressed under 50-800 MPa with die-wall lubrication, heated in the air for dewaxing and sintering at the rate of 10°C/min to 1600°C, and held at the temperature for 2 hr.
The spring-back of the alumina was larger than those of the iron and copper powders and smaller than those of the spray-dried alumina-based ceramic granules. The axial spring-back by ejection showed the minimum for the optimum binder content. Increased compacting pressure led to increased axial spring-back by the unloading, decreased axial spring-back by the ejecting, and decreased shrinkage during the sintering.
The titanium carbide granules, -140+200 mesh in size, containing 0.5 mass% of polyvinyl alcohol were prepared from a powder with an average particle size of 3.4 μm. They were pressed under 400 and 800 MPa in a die lined with zirconia and having a bore diameter of 10 mm. The electrical conductivity was measured by discharging a constant current to the compacts.
The drop of the conductivity, indicating the occurrence of the microcracking in the ceramic compacts, was larger for the ejecting than for the unloading.抄録全体を表示PDF形式でダウンロード (1489K) -
田上 耕司, 石丸 淳一, 正岡 英二, 藤井 浩二, 松田 日出彦1988 年 35 巻 6 号 p. 479-485
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーTensile tests, creep tests and SEM observation of fractured surfaces are made to investigate deformation characteristics of sintered tungsten wires of 1.0 mm in diameter at intermediate temperatures. The failure occurs with no cup-and-cone fracture because of the chisel-edge type failure of individual fibers, giving several microcracks running along the separated fibers in the radial directions at the temperature range of 600 to 800 K. The number of microcracks decreases with increasing temperature and the double cupped fracture is observed at 1300 K. Typical curves are obtained from creep tests and the stress exponent of steady-state creep rate is about 7 characteristic of the sintered materials in which subgrains do not form during creep. The ratio of the activation energy for steady-state creep to the lattice diffusion energy is then calculated to be less than 0.5, which may result from the active short-circuit diffusion through many boundaries of fibers in the present material.抄録全体を表示PDF形式でダウンロード (5669K) -
戸田 堯三, 松山 厳1988 年 35 巻 6 号 p. 486-491
発行日: 1988/09/25
公開日: 2010/07/12
ジャーナル フリーThe effects of BeO addition (0-2 wt%) on the pressureless sintering process and the transparency of yttria were studied. The addition of BeO (0.1-0.5 wt%) promoted the sintering of Y2O3 to decrease markedly the residual pores in sintered bodies above 2100°C. The transparency of sintered Y2O3 was independent of compacting pressure (1-10 t/cm2). BeO vaporized with the increase of sintering temperature and more than half of the initial contents of BeO decreased above 1800°C. The transmittance (thickness 1.0 mm, wavelength 300-7000 nm) of the 0.1 wt% BeO-Y2O3 sintered at 2150-2250°C for 50-300 min. in H2 was 80%. It was suggested that the liquid phase formation of Y2O3-BeO system and the vaporization of BeO contributed to the fabricating of the transparent Y2O3.抄録全体を表示PDF形式でダウンロード (2636K) -
黒木 英憲, 菊本 守, 大森 正信, Richard A. Queeney1988 年 35 巻 6 号 p. 492-498
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーThe die cavity, 40 mm in diameter, was filled step by step with electrolytic iron and copper powders alternately. Then, the layered columns of the powders were pressed, sintered and HIPed to solid laminated composites of 2-16 layers.
At -196°C, the load/deflection curves and the ultimate tensile strength of the composites varied with the number of layers. In some of the 8 and 16 layer-composites, the iron layers were fractured continually into shorter and shorter lengths at -196°C, leading to somewhat larger elongation of the composites.
In the crack divider type of impact specimens, a pair of shear lips was formed at a low temperature on the fracture surface of each iron layer constructing a composite. As the number of layers was increased, the shear lips amounted to a certain area of ductile fracture and resulted in a decrease of the ductile-brittle transition temperature.
In the crack arrester specimens, the extent of the delamination increased as the number of layers was decreased. This prevented the cracking in the next iron layer before delamination took place, and resulted in a rather high impact strength.抄録全体を表示PDF形式でダウンロード (5011K) -
鎌田 政智, 阿南 吾郎, 徳永 洋一1988 年 35 巻 6 号 p. 499-504
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーSintered low alloy steels with the composition of 2%Si-3%Ni-O0.6%C were austempered or quenched in water and tempered after (α+γ) solution treatment, then, the effect of their structures on the tensile nronerties was studied. The results are summarized as follows:
Ferrite played an important role in improving the ductility of the specimens with mixed structure of ferrite (α), upper bainite (B), and retained austenite (γR).
Both in sintered (α+β+γR) tri-phase steels and (α+tempered martensite) dual-phase steels, the elongation increased and the strength decreased with increasing the volume fraction of a-phase. In connection with this behavior, as the ratio of hardness of harder phase to that of a-phase increased, the relation between tensile properties and the volume fraction deviated from a linear relationship.
A model for the tensile fracture process of the specimen with (50 vol%α+β+γR) mixed structure was proposed. The growth and the coalescence of secondary voids in the a-phase or at the α/(β+γR) interface resulted in the propagation of ductile cracks.抄録全体を表示PDF形式でダウンロード (4202K) -
土屋 信次郎, 斎藤 実, 寺田 修, 鈴木 寿1988 年 35 巻 6 号 p. 505-510
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーBy using reduced and carburized starting powder, SKH57 was vacuum-sintered, HIP-ed and then heat-treated. Then, its mechanical properties were studied as a function of sintering temperature (TS), quenching temperature (TQ), aging temperature (TA), etc. The following results were obtained. Under a suitable condition such as TS=1200°C, TQ=1170-1200°C and TA=560-590°C, the sintered alloy showed excellent properties such as 4.8-4.9GPa of TRS and 840-870 HV. The alloy commonly fractured from a small flat region (φ10-20μm) containing micropores along the former austenite grain boundaries. The micropores were considered to be caused by the reduction of a small amount of remained oxides, which took place during sintering. The strength of the alloy, therefore, was controlled by the size of flat region, but not by the primary carbide or the former austenite grain size.抄録全体を表示PDF形式でダウンロード (5733K) -
黒鉛を含む銅―ニッケル―すず系の粉末圧延条件について山田 眞二, 菅藤 昭良, 松田 哲也, 長島 茂夫, 白坂 康広, 跡部 敏郎1988 年 35 巻 6 号 p. 511-516
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーFor the purpose to develope the self-lubricating sintered plates having high wear resistances for pressing machines and general industrial machines, powder rolling of premixed powders consists of Cu-28 wt%Ni-8 wt%Sn-5 wt%Fe-7 wt%(15P-Cu)-5 wt%C containing hydroxypropyl cellulose as an organic binder was performed using a mill with a working roll diameter of 600 mm. Thicknesses and apparent densities of rollcompacted sheets were measured, and the tensile strength of sintered sheets was investigated.
Results obtained are as follows:
(1) Keeping a constant depth (55 mm) of feed powder in hopper, the rolling load depends on the roll gap at the conditions of roll speeds from 0.3 to 0.7 m/min and the apparent density of green sheet increases gradually from 5.5 to 6.6 g/cm3 as the rolling load rises.
(2) The tensile strength of roll-compacted sheets produced at roll speed 0.3 m/min, roll gap -0.2, 0 and +0.3 mm respectively depends on the sintering temperature, and the sheet after sintering for 40 min at 1250 K showed the tensile strength of maximum 160 MPa.抄録全体を表示PDF形式でダウンロード (2884K) -
上山 守, 町井 洋一1988 年 35 巻 6 号 p. 517-520
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーWe studied the effects of alumina particle diameter and flux specific surface area on the powder packing density of green sheet. When the alumina particle diameter was in the range 0.8 to 3.6pm and the flux specific surface area was 1 to 20 m2/g, the packing density was 61 vol%, nearly the same as the theoretical packing density (60.45 vol%) of monosized powder of single stagger arrangement.
However, the packing density decreased to 60 vol% when the particle diameter was 0.5μm. It also decreased to 55 vol% or to 38% when the flux specific surface area was 100 m2/g, or 380 m2/g, as for alumina/ flux powder mixture, the larger the alumina particle diamater and the smaller the flux specific surface area, the higher became the packing density. The packing density of alumina green sheet remained unchanged (61 vol%) even when the amount of binder varied within the range 3 to 18 weight%. When the amount of binder was more than 18 weight%, the packing density decreased linearly as the amount of binder increased, regardless of whether the binder was polyvinyl butyral or polymethylmetacryrat.抄録全体を表示PDF形式でダウンロード (285K) -
加藤 哲男, 草加 勝司, 洞田 亮1988 年 35 巻 6 号 p. 521-525
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーThe objective of this work was mainly to elucidate the potential of Ti-Al type P/M intermetallics for higher temperature structural applications. Investigations were made firstly on titanium aluminides for Al; 26-80% and then on TiA1-B(-Si) type intermetallics containing B and Si of less than 0.124 and 4.6%, respectively.
The results were summarized as follows:
(1) Morphologies of titanium aluminides such as Ti3Al, TiAl and TiAl3 are highly varied under the influence of Ti-Al binary equilibrium diagram. They, mostly meta-stable as rapidly quenched, fairly change in Ti3Al/TiAl phase boundary and other microstructures of particles after heat-treated and hence from Ti3Al/TiAl>TiAl3>TiAl (S) to TiAl3>TiAl (S)>TiAl in the order of microhardness.
(2) Titanium aluminide specimens (of full density) are successfully prepared by specific double-stage HIP process, with the view of preventing titanium alloy powders from metallurgically reacting with HIP container materials. They, HIP'ed in such a way, show a minimum microhardness and relatively, nonbrittleness for the stoichiometric TiAl (γ).
(3) Hot ductility of TiAl (at 900°C) may be appreciably improved by the B-addition of about 0.05% (hot tensile strength ge; 30 kgf/mm2), although greatly dependent on HIP temperature. On the other hand, tensile strength at ambient temperature (RT) proves to be more than 40 kgf/mm2.
(4) Hot ductility of TiAl firstly increases with Si-addition and then reaches a maximum elongation of almost 50% in the vicinity of Si: 3%, while hot tensile strength keeps nearly 30 kgf/mm2. Excess Si-additive leads to a salient decline of hot ductility and also RT tensile strength possibly due to TiSi type precipitates.抄録全体を表示PDF形式でダウンロード (3703K) -
上山 守, 和田 弘, 上原 秀秋1988 年 35 巻 6 号 p. 526-531
発行日: 1988/09/25
公開日: 2009/12/04
ジャーナル フリーWe studied the effect of alumina content on the sinterability of alumina substrate in relation to the firing temperature. The surface roughness, sintered density, and bending strength of alumina substrate were improved as the alumina content increased. The optimum firing temperature for alumina substrate was defined as the minimum temperature at which the characteristics of alumina substrate were satisfied all the following conditions, 1) The ratio of water absorption is almost zero. 2) The ratio of the sintering shrinkage is 0 to -0.4% of the maximum sintering shrinkage. 3) The sintering density is above 97% of the maximum sintering density. 4) The average surface roughness is 1.3 times of the minimum surface roughness. 5) The bending strength is above 85% of the maximum bending strength. The optimum firing temperature shifted toward higher-temperature side when the content of alumina increased. Thus, the optimum firing temperature for 1.1μm alumina substrate was 1, 520°C for an alumina content of 91.5% 1, 560°C for 96.4%, and 1, 600°C for 98.8%.抄録全体を表示PDF形式でダウンロード (4294K) -
勝村 祐次, 小林 正樹, 小堀 景一, 鈴木 寿1988 年 35 巻 6 号 p. 532-537
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーThe Al2O3-SiC mixed powder with additional SiO2 powder and pre-oxidized Al2O3-SiC mixed powder containing SiO2 were hot-pressed in Ar. The sinterability of these starting powders were examined comparing with the Al2O3-SiC mixed powder free from SiO2. The structures and transverse-rupture strength (T.R.S.) of hot-pressed ceramics were also examined.
It was found that the sinterability of Al2O3-SiC mixed powder was markedly improved with containing over 2-3% SiO2. This was considered to be due to mullite formation and appearance of mullite-SiO2 eutectic liquid during the period of rising temperature to hot-pressing one. With increasing SiO2 contents, the microstructure became locally coagulated and T.R.S. decreased slightly. As the fracture source, an even area of φ70-80 μm, probably due to the coagulated structure, was observed. These results were in detail discussed.抄録全体を表示PDF形式でダウンロード (4006K) -
田代 新二郎, 辻 雄二, 山下 洋八, 五十嵐 秀二1988 年 35 巻 6 号 p. 538-542
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーThe powder of (Pb, Ba) (Zn, Mg, Nb, Ti)O3 system ceramics developed as the multilayer capacitor material with the optimum firing temperature of 1100°C was mixed with small amount of excess PbO as a sintering aid and ground to submicron by ball-milling using the partially stabilized zirconia balls of 3 mmφ. Microstructures such as density, grain size or liquidus phase of the ceramics fabricated from the powders were examined as a function of excess PbO content by SEM and DTA. Densification was enhanced by addition of excess PbO at the firing temperature lower than 1000°C, and the dense ceramic bodies above 7.7 g/cm3 with small grain were obtained at firing temperature of 750°C. Temperature dependence of dielectric constants were measured by a LF inpedance analyzer at 1 kHz. For the 2 mol%PbO added ceramics sintered at 800°C, relative permittivity at room temperature higher than 10000 was successfully attained without remarkable change of loss factor and insulation resistance from those of the stoichiometric ceramics sintered at 1100°C.抄録全体を表示PDF形式でダウンロード (2553K) -
横田 勝, 藤井 孝浩, 永井 宏, 庄司 啓一郎1988 年 35 巻 6 号 p. 543-547
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーStudies on the wettability and the bonding of Cu-Sn-Ti system (pure metals except for Ti, binary alloys and a ternary alloy) against sintered Al2O3 compacts were carried out. Results obtained were as follows:
(1) Wettability of Cu, Sn pure metals, Cu-10%Sn and Cu-5%Ti binary alloys in vacuum (1.3×10-2-4.0×10-3 Pa) were unsatisfactory. On the other hand, Cu-10%Sn-5%Ti ternary alloy was comparatively wettable, where reaction layer corresponding to Ti3Al containing slight Cu and Sn was formed in the interface between brazing alloy and sintered Al2O3 compact. Sn-5%Ti binary alloy against sintered Al2O3 showed fairly excellent wettability, but did not form any reaction layer between them.
(2) Bonding strength of sintered Al2O3 compacts brazed with Cu, Sn pure metals and Cu-10%Sn or Cu-5%Ti binary alloys had a tendency to decrease with increasing the degree of vacuum (or with decreasing oxygen partial pressure) of bonding atmosphere. Bonding strength of sintered Al2O3 compacts brazed with Sn-5%Ti and Cu-l0%Sn-5%Ti alloys which were good wettable to sintered Al2O3 were comparatively high, and those had a tendency to increase with raising bonding temperature.抄録全体を表示PDF形式でダウンロード (5032K) -
貞廣 孟史, 蕎麦 田薫1988 年 35 巻 6 号 p. 548-551
発行日: 1988/09/25
公開日: 2009/12/04
ジャーナル フリーRelationship between rupture strength and fracture toughness determined by Bridge Indentation method for WC-(5.5-40) mass%Co alloys was studied.
The results obtained are as follows:
(1) Fracture toughness estimated by taking account of the yielding of the plastic zone at the tip of defect agrees with the measured value by the BI method.
(2) On the relationship between rupture strength and fracture toughness, the rupture strength follows a linear elastic fracture mechanics and increases with fracture toughness in the case of large defect. While in the case of small defect, the rupture strength increases to the maximum strength which reaches near the yield strength, and decreases with an increase in fracture toughness. Rupture strength variation with fracture toughness depends on the defect size and the plastic zone.抄録全体を表示PDF形式でダウンロード (272K) -
李 世欽, 鈴木 清, 中川 威雄1988 年 35 巻 6 号 p. 552-557
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーFor further development of the high performance self-lubrication materials being proof against vacuum or high temperature, cast iron fibre composites containing a large amount of graphite were investigated. The cast iron fibre of 20-40 μm in diameter and 1.2 mm in length, which was prepared by chatter-machining a ductile cast iron bar, was mixed with graphite powder and consolidated by compacting in a die, sintering and finally repressing. The optimum conditions for the processing were determined experimentally, and the composite of the almost same mechanical strength as grey iron was made with an addition of 28.8 vol% graphite. In conclusion the fibre metallurgical processing of the high performance self-lubrication composite materials of cast iron and graphite is feasible in the production.抄録全体を表示PDF形式でダウンロード (3375K) -
金子 武, 天野 良成1988 年 35 巻 6 号 p. 558-562
発行日: 1988/09/25
公開日: 2009/05/22
ジャーナル フリーThe effect of heat-treatment in vacuo and hydrogen on ductility and UTS of the sintered 95.5 W-3.0 Ni-1.5 Fe and 91.3 W-5.8 Ni-2.9 Fe (by wt%) heavy alloys has been studied. The influence of composition and microstructure upon the mechanical properties of the cold worked (swaging) alloys is also presented in this paper.
These materials were heated at 400-1200°C in hydrogen atmosphere and in vacuo, and the mechanical properties of heat treated alloys were tested.
The effect of vacuum treatment was attributed to the removal of hydrogen embrittlement, and values of UTS and elongation increased after the vacuum treatment.
The scanning electron micrographs of the fracture surfaces showed that hydrogen weakens mainly the interface between tungsten-matrix phase boundaries, and W-grain boundaries.
High ductility was found to be connected to a high binding strength between the tungsten grains and the matrix phase.抄録全体を表示PDF形式でダウンロード (1305K)
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